How do I get at this?

I managed to sit out for a while this afternoon before the showers began and had great fun watching this woodpigeon trying to get at the birdseed. It tried all sorts for at least 15 mins but wasn't successful.
Why is the food in a cage you might (or might not) ask?
Last week we had seed in the bird feeder but the seed falling on the grass was attracting increasing numbers of feral pigeons who we didn't want, esp as they were damaging the plants, so I decided to see if I could attract the small birds whilst keeping the pigeons away.
So far success is limited - the pigeons (apart from this one) haven't returned but so far there haven't been any small ones, either.